The present disclosure relates to a liner for a gas turbine combustor, a flow sleeve for a gas turbine combustor, and a gas turbine combustor, and more particularly, to a liner, a flow sleeve and a gas turbine combustor each having a cooling sleeve.
A turbine is a mechanical device that extracts an impulsive or repulsive force from a flow of a compressed fluid like gas and converts it into a rotary force. If steam is used as the fluid, it is called a steam turbine, and if combustion gas is used as the fluid, it is called a gas turbine.
The thermal cycle of the gas turbine is the Brayton cycle, and the gas turbine is composed of three main components, that is, a compressor, a combustor, and a turbine. According to the operating principle of the gas turbine, air is first absorbed in the atmosphere and compressed by way of the compressor, the compressed air is sent to the combustor and produced as high temperature, high pressure gas operating the turbine, and finally, exhaust gas is emitted to the atmosphere. Accordingly, the thermal cycle of the gas turbine includes four processes, that is, compression, heating, expansion and heat radiation.
The compressor of the gas turbine absorbs air from the atmosphere and supplies the air for combustion to the combustor, and in this case, the pressure and the air temperature in the compressor are increased through adiabatic compression.
The combustor mixes the compressed air supplied from the compressor with fuel and burns the mixture to produce combustion gas having high energy, and through an isobaric combustion process, the temperature of the combustion gas is raised up to a temperature limit of the combustor and the turbine.
The high temperature, high pressure combustion gas produced from the combustor is expanded in the turbine, and the expanded gas gives an impulsive or repulsive force to the rotary blades of the turbine, thus converting it into mechanical energy. The mechanical energy made in the turbine is supplied as energy to compress air to the compressor, and the remainder is used to drive an electric generator, thus producing power.
Since the main components of the gas turbine have no reciprocal motions like a piston and a cylinder, there are no frictional portions between them, so that advantageously, an amount of lubricating oil is extremely small, the amount generally used in the reciprocating motion mechanism are substantially reduced, and high speed motions are taken.
The present disclosure relates to the combustor of the gas turbine as mentioned above.
FIG. 1 is a schematic sectional view showing a gas turbine combustor. As shown in FIG. 1, a combustor 10 of the gas turbine largely includes an ignition part 50, a liner part 100 and a transition piece part 200.
The ignition part 50 serves to ignite fuel, and the liner 100 is an energy generation part that mixes the fuel with compressed air and converts high temperature gas into motion energy to drive a turbine. The transition piece part 200 is connected to the liner part 100 and sends the high temperature gas, while increasing the velocity of the gas.
Since the combustion occurs in the liner part 100, the temperature of the liner part 100 becomes increased, and accordingly, cooling the liner part 100 is very important in effective operation of the turbine.
FIG. 2 is a side sectional view showing the liner part 100 in the gas turbine combustor. As shown in FIG. 2, the way of cooling a liner 110 in the liner part 100 can be checked. The liner part 100 includes the liner 110 and a flow sleeve 120 adapted to encompass the liner 110. The flow sleeve 120 has cooling holes 130 formed therein to allow air (hereinafter, referred to as jet flows) introduced through the cooling holes 130 to vertically collide against the liner 110, thus cooling the liner 110.
However, as the liner part 100 is connected to the transition piece part 200, the collision cooling becomes under the influence of air (hereinafter, referred to as cross flows) introduced from the transition piece part 200 into a space portion 140 between the liner 110 and the flow sleeve 120 of the liner part 100.
FIG. 3 is a side sectional view showing the transition piece part 200 in the gas turbine combustor. As shown in FIG. 3, a perforated sleeve 220 is adapted to encompass a transition piece 210, and through the cooling of the perforated sleeve 220, the air to be emitted to the compressor moves and collides against the transition piece 210, thus cooling the transition piece 210. After that, the cooled air moves along an annular pipe in a space portion 240 between the transition piece 210 and the perforated sleeve 220 and then moves along another annular pipe in the space portion between the liner 110 and the flow sleeve 120. Accordingly, the cooled air vertically collides against the jet flows moving toward the surface of the liner 110 of the combustor 10 from the cooling holes 130 of the flow sleeve 120. The formation of such cross flows reduces the cooling effect in the region of the liner 110 against which the heat of the jet flows passing through the flow sleeve 120 collides. That is, a substantially low heat transfer rate occurs on the surface of the liner 110. Such low heat transfer rate causes a high temperature on the surface of the liner 110, which results in the loss of strength. Accordingly, the life span of the liner 110 becomes shortened, which undesirably needs frequent exchanging.